The cases range from the gruesome to the mysterious — a police shooting, a drug overdose, an accident, a cold-blooded murder.

In some, the Victorian coroner couldn't work out the cause of death, while in others it appeared cut-and-dry.

But after years of frustration, and the undeniable inkling that the coroner missed something, several Victorian families are petitioning for their cold cases to be prised open again.

It's sparked a legal battle over whether the coroner even has the power to open fresh inquests.

In 1999, the power to reopen historical inquests shifted from the Supreme Court to the Coroner.

So Slater and Gordon's Naty Guerrero-Diaz says, "The question is: what happens when you have an inquest that occurred before the 1999 changes, but you're asking a coroner of today to reopen the inquest?"

"Does the law that was in place at the time of the inquest apply? Or does the law that is in place now apply?"

Today, the family of Maria James — who was murdered in the back of her Melbourne bookshop in 1980 — will ask the Supreme Court to resolve this legal limbo.

If the court declares it is the coroner who has jurisdiction to reopen the James inquest, it could also end the similar painful holding pattern for six other Victorian families.

The stabbing of Maria James

Ms James was stabbed to death in the back of her secondhand bookshop in Thornbury.

For 33 years, police were baffled as to a motive, until in 2013 Maria's youngest son, Adam James, dropped the bombshell that he'd been abused by Father Anthony Bongiorno three times in the months leading up to his mother's death.

The bloodied pillow that police thought had yielded the killer's DNA was actually from a completely different crime scene and had nothing to do with Ms James.

This means everyone is back in the frame, including Father Bongiorno, and his colleague, Father Thomas O'Keeffe, the parish priest at St Mary's Thornbury, who Mr James said also abused him.

Both priests have since died.

The James family has seemingly faced hurdles at every turn, each more bizarre than the last — for example, their mother's bloodied quilt, which could hold traces of the killer's blood, has disappeared, along with important documents about the investigation.

"All this together with the intervention of a clairvoyant make the ingredients of a good B grade screenplay.

"The facts in my view do not justify my concluding Laurence Prendergast is dead."

He instead found Mr Prendergast had a strong incentive to go missing intentionally. But according to legal sources, the more that time marches on, the more unlikely it is he's hiding out somewhere behind another identity.

Mr Gurvich's acknowledgement that Mr Prendergast could have been abducted and murdered now seems more likely.

The death of Oswaldo Diaz-Lopez

On the day he died, Oswaldo Diaz-Lopez was repairing his son's 1978 Mercedes sedan.

The 56-year-old certainly had the know-how. He was a retired fitter and turner and he was good with his hands.

But the coroner found that the hydraulic trolley jack that he was using to suspend the car either "slowly collapsed or slipped", trapping him.

"Mr Diaz-Lopez contributed to his own death by working under the vehicle without taking appropriate additional safety precautions," the coroner wrote.

He was found under the car by his other son, Christian, who found the jack lying on its side.

In this case the applicant, whose identity is still unknown, has asked for the findings to be set aside, which would lead to a new investigation.